Why is it questionable to write Flash prototypes early in the design process?

Solution

As soon as people write code, they seem to be hesitant to throw it away and write new code.
So with the first piece of code the design of a system is basically set in stone.
Buy using early prototyping techniques like paper prototyping you can delay the first piece of code and so have more time to redesign your system before you commit too much.
Throwing away paper doesn't hurt, throwing away code does.